| 其他摘要 | To find out the effect of different kind land use patterns and different lithological conditions on soil infiltration in Karst area. In this study, with different land use types, chosing the underlying surface of the limestone and dolomite slope as the research objects with typical human activities, and measured soil steady infiltration by the Guelph Permeameter. This study reveal the process of soil infiltration of different lithology, the key mechanism controlling factors and human activities on soil infiltration,etc, then extract the typical significance of soil moisture infiltration experiments data in Southwest Karst slopes. Combined with soil moisture parameters , and soil moisture and soil water potential field monitoring data, find out effective solutions of farmland drought in karst areas. The main results are showed as followed, (1) There is a big difference between limestone and dolomite soil about soil properties. Limestone soils with high organic content, porosity and better soil structure, while dolomite with low nutrient content and high sand content. When the land use from forest land into grazing shrub, the two types of surface soil showed the same trend, bulk density and clay content increased, porosity and organic content decreased. (2) Under undisturbing land use condition, Ks of limestone and dolomite soil are very high, average value are 0.548cm/min and 0.429cm/min respectively. Compare to dolomite slope, the space distribution of K on limestone slope seems have more heterogeneities that coefficients of variations (CV%) was between 90.71%～95.62%. (3) Under the influence of over grazing disturbance, the Ks of limestone and dolomite soil decreased significantly that average values decreased 52.2% and 86.7% respectively. (4)Limestone and dolomite sloping fields’ shallow and deep soil moisture have same trend, shallow soil moisture increasing, deep soil moisture following; soil moisture decreasing have the same trend. But deep soil moisture changes delayed. (5)Limestone slope cropland and stone nook ground’s soil moisture changes have same trend, but have differences. Stone nook ground much easier reach to water stress point and permanent wilting point(-620kPa). During the monitoring period, the stage of slope cropland drought occurred in 7and 8 months, while stone nook ground occurred in 7, 8 and 9 months and last much longer. (6) Compared with limestone soil, dolomite sand moisture changes much more violently, poorer water-holding, and soil moisture volatile easier. (7)According the local topography, crop cultivation, and steady infiltration rate, take different anti-drought measures on limestone soil and dolomite soil . Limestone slopes using tractor road and road ditch pond water-saving systems, dolomite slope add adopted aquasorb into dolomite sand to increase soil water. Two types of programs have achieved good results. |
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